CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Comprehensive income (loss), net of tax
Net income	$ 582,716	$ 281,882	$ 442,099
Other comprehensive income (loss)
Net unrealized gain (loss) on securities	84,703	(17,075)	89,415
Reclassification of net realized (gain) loss on securities into earnings	37,724	(7,308)	(64,310)
Total other comprehensive income (loss)	122,427	(24,383)	25,105
Total comprehensive income	705,143	257,499	467,204
Comprehensive income attributable to noncontrolling interests	78,263	13,246	89,222
Comprehensive income attributable to common stockholders	$ 626,880	$ 244,253	$ 377,982